GEOID12B for Google Earth (GeoidGE)

GeoidGE is a graphical front end for the NGS online tool, GEOID12B, that eliminates the need to input geodetic coordinates and displays the converted height, geoid separation, and scale factor in a placemark balloon. Both ellipsoid-to-orthometric and orthometric-to-ellipsoid height conversions are supported. Default input height is provided by the Google Elevation API as an approximation of NAVD88 orthoheight.

1. Position the point of interest (POI) in the center of the view. One way to do this is to double-click an unmarked location. To precisely position the POI in the center of the view, add a placemark at the desired location; then edit the properties of that placemark and reset the view (explain). For best results, disable automatic tilting (Tools, Options, Navigation, Do not automatically tilt while zooming) and minimize elevation exaggeration (Tools, Options, 3D View, Elevation Exaggeration, 0.01).
2. Check the box beside the Ellipsoid Height Conversion network link. A form will be presented with read-only coordinates corresponding to the view center and input fields for height and type. Converted height, geoid separation, and scale factor are displayed when the Convert button is pressed.
3. On subsequent uses, reposition the POI and ensure that the network link is checked and selected. Then choose Refresh from the Edit menu, or right-click and select Refresh in the context menu (explain).

Image NGS

Coverage includes the conterminous United States, Alaska, Hawaii, Puerto Rico, the Virgin Islands, American Samoa, Guam, and the Northern Mariana Islands. Check the Extents folder to display the coverage area bounding boxes.

Note: To save GeoidGE results from one Google Earth session to another, right-click on Saved Placemarks and select Save to My Places or Save Place As.

All data are retrieved from remote servers. Data errors, accuracy, and availability are beyond the control of this application.